Apparatus including 4-way valve for fabricating semiconductor device, method of controlling valve, and method of fabricating semiconductor device using the apparatus

ABSTRACT

An apparatus and method for fabricating a semiconductor device using a 4-way valve with improved purge efficiency by improving a gas valve system by preventing dead volume from occurring are provided. The apparatus includes a reaction chamber in which a substrate is processed to fabricate a semiconductor device; a first processing gas supply pipe supplying a first processing gas into the reaction chamber; a 4-way valve having a first inlet, a second inlet, a first outlet, and a second outlet and installed at the first processing gas supply pipe such that the first inlet and the first outlet are connected to the first processing gas supply pipe; a second processing gas supply pipe connected to the second inlet of the 4-way valve to supply a second processing gas; a bypass connected to the second outlet of the 4-way valve; and a gate valve installed at the bypass.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 12/980,633, filed Dec. 29, 2010, which is adivisional application of U.S. patent application Ser. No. 11/321,491,filed on Dec. 29, 2005, which claims the benefit of Korean PatentApplication No. 10-2005-0005074, filed on Jan. 19, 2005, and KoreanPatent Application No. 10-2005-0076968, filed on Aug. 22, 2005, in theKorean Intellectual Property Office, the contents of which areincorporated herein in their entirety by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus for fabricating asemiconductor device, and more particularly, to an apparatus forfabricating a semiconductor device using a 4-way valve with improvedpurge efficiency by improving a valve system for gas supplied to areaction chamber, a method of controlling the 4-way valve, and a methodof fabricating a semiconductor device using the apparatus.

2. Description of the Related Art

Semiconductor devices are fabricated by repeatedly performing processessuch as deposition and patterning of a thin layer on a surface of asubstrate, i.e., a wafer. Deposition and patterning of a thin layer isusually performed in a semiconductor process module. A semiconductorprocess module has a configuration that differs depending on a processto be performed in fabrication of a semiconductor device, but itfundamentally includes a reaction chamber defining a reaction area inwhich a wafer is loaded and hermetically sealed and a valve system whichsupplies a gas material to the reaction chamber.

Chemical vapor deposition (CVD) or atomic layer deposition (ALD) areusually used to deposit a thin film on a wafer through a chemicalreaction of a gas material. Unlike physical deposition using sputtering,CVD and ALD are similar to each other in that they use chemical reactionbetween two or more gas materials. However, in CVD, multiple gasmaterials are simultaneously supplied to a reaction area in a reactionchamber including a wafer so that a reaction product is deposited onto asurface of the wafer from above. In contrast, in ALD, multiple gasmaterials are sequentially supplied to the reaction area in the reactionchamber so that chemical reaction between the gas materials is limitedto only the surface of the wafer.

Despite a disadvantage that the ALD is slow in deposition since thechemical reaction is limited to only the surface of a wafer, ALD isessential to fabrication of a dielectric layer, a diffusion preventinglayer, a gate dielectric layer, etc., for a memory capacitor thatrequires a high-purity and high-uniformity thin film. ALD isadvantageous in that deposition and thickness of a thin film whosethickness is decreased with the micronization of a semiconductor devicecan be controlled precisely.

Due to the characteristics of the ALD, a purge process of removing gasremaining in a reaction chamber before and after a gas material issupplied to the reaction chamber when gas materials are sequentiallysupplied is mandatory.

FIG. 1 is a schematic diagram illustrating a gas valve system of aconventional ALD apparatus in which ALD is performed. FIG. 2 is anenlarged view of a part of the gas valve system in which dead volume(DV) occurs. FIG. 3 is a cross sectional view of the part shown in FIG.2, taken along the line AA', in which a 2-way valve is closed. FIG. 4 isa cross sectional view of the part shown in FIG. 2, taken along the lineAA', in which the 2-way valve is open.

The conventional ALD apparatus and ALD using the same will be describedbriefly with reference to FIGS. 1 through 4.

Referring to FIG. 1, a source gas supply source 22, a reactive gassupply source 24, a purge gas supply source 28, a first carrier gassupply source 26, and a second carrier gas supply source 30 supply asource gas S1, a reactive gas S2, a purge gas P2, and carrier gases P1and P3, e.g., argon gases, respectively, to a reaction chamber 10 via asource gas supply pipe 22 a, a reactive gas supply pipe 24 a, a purgegas supply pipe 28 a, a first carrier gas supply pipe 26 a, and a secondcarrier gas supply pipe 30 a, respectively.

A discharge pump 12 is installed at the back of the reaction chamber 10to control the inner pressure of the reaction chamber 10. A throttlevalve 14 is installed between the reaction chamber 10 and the dischargepump 12 to maintain the inner pressure of the reaction chamber 10constant.

-   -   In a source gas supply line, the first carrier gas supply pipe        26 a is connected to and extended from the first carrier gas        supply source 26 to supply the carrier gas P1. The source gas        supply source 22 is connected in parallel through first and        second 3-way valves 32 and 34. An on/off valve, i.e., a first        2-way gate valve 42 is installed between the first and second        3-way valves 32 and 34. A bypass 16 is connected to the first        carrier gas supply pipe 26 a in the back of the second 3-way        valve 34 through a third 3-way valve 36. An end of the bypass 16        is connected between the throttle valve 14 and the discharge        pump 12 on a discharge pipe 13. An end of the first carrier gas        supply pipe 26 a is connected to the purge gas supply pipe 28 a        through a fourth 3-way valve 38.

In a purge gas supply line, the purge gas P2 is supplied from the purgegas supply source 28 to the reaction chamber 10 through the purge gassupply pipe 28 a. The fourth 3-way valve 38 is installed at a junctionof the purge gas supply pipe 28 a and the first carrier gas supply pipe26 a. A second gate valve 44 is installed between the purge gas supplysource 28 and the fourth 3-way valve 38.

In a reactive gas supply line, the carrier gas P3 is supplied from thesecond carrier gas supply source 30 to the reaction chamber 10 throughthe second carrier gas supply pipe 30 a and the reactive gas S2 issupplied from the reactive gas supply source 24 to the reaction chamber10 through the reactive gas supply pipe 24 a and the second carrier gassupply pipe 30 a to which the reactive gas supply pipe 24 a isconnected. A third gate valve 46 is installed between the reactionchamber 10 and the junction of the reactive gas supply pipe 24 a and thesecond carrier gas supply pipe 30 a. A fourth gate valve 48 is installedbetween the junction and the reactive gas supply source 24.

The open/closed state of the inlet and outlet of the third and fourth3-way valves 36 and 38 will be described with reference to FIGS. 2through 4. Unlike FIGS. 2 through 4, FIG. 1 just functionallyillustrates the inlet and outlet of the third and fourth 3-way valves 36and 38 according to a flow direction of supplied gas.

The third and fourth 3-way valves 36 and 38 are diaphragm valves. A flowof a gas material according to on/off of the third 3-way valve 36 willbe described. The third 3-way valve 36 installed at the junction of thefirst carrier gas supply pipe 26 a and the bypass 16 includes a firstvertical via hole 36 h 1, which is vertically connected to the firstcarrier gas supply pipe 26 a penetrating straight through a body 36 c,and a second vertical via hole 36 h 2 which is vertically connected toan end of the bypass 16. A diaphragm 36 e moved up and down by apressure is installed above a surface of the body 36 c through which thefirst and second vertical via holes 36 h 1 and 36 h 2 are exposed withina housing 36 d to define a predetermined space.

When the third 3-way valve 36 is turned off, that is, when the diaphragm36 e moves downward and closely contacts the surface of the body 36 c toclose the first and second vertical via holes 36 h 1 and 36 h 2, asshown in FIG. 3, the first carrier gas supply pipe 26 a is open andenables the first carrier gas P1 or the source gas S2 to flow to thefourth 3-way valve 38, but a gas flow to the bypass 16 is blocked.

When the third 3-way valve 36 is turned on, that is, when the diaphragm36 e moves upward and is separated from the surface of the body 36 c toopen the first and second vertical via holes 36 h 1 and 36 h 2, as shownin FIG. 4, the first carrier gas supply pipe 26 a is open and enablesthe first carrier gas P1 or the source gas S2 to flow to the fourth3-way valve 38, and simultaneously, a gas material flowing out throughthe first vertical via hole 36 h 1 passes through a space between thesurface of the body 36 c and the diaphragm 36 e and flows into thebypass 16 through the second vertical via hole 36 h 2.

Referring to FIGS. 1 through 4, regardless of the on/off state of thethird 3-way valve 36, a second outlet 36 b of the third 3-way valve 36is open. Accordingly, whether the first carrier gas P1 or the source gasS1 is supplied to the reaction chamber 10 through the third and fourth3-way valves 36 and 38 depends on whether an inlet 38 b of the fourth3-way valve 38 is open or closed. As a result, when the inlet 38 b ofthe fourth 3-way valve 38 is closed, the first carrier gas P1 or thesource gas S1 does not flow to the fourth 3-way valve 38 but flows intothe bypass 16 even when the second outlet 36 b of the third 3-way valve36 is open.

A process of depositing a reaction product S1+S2 to form a thin film ona surface of a substrate using ALD using the source gas S1 and thereactive gas S2 will be described below.

In a source gas pulsing stage, the source gas S1 is supplied to thereaction chamber 10 loaded with a wafer, i.e., the substrate (not shown)so that a source gas material is attached to a surface of the substrate.Here, the first gate valve 42 is turned off to be closed; a first outlet32 a of the first 3-way valve 32 is open; an inlet 34 a and an outlet 34b of the second 3-way valve 34 are open; a first outlet 36 a of thethird 3-way valve 36 toward the bypass 16 is closed; the second outlet36 b of the third 3-way valve 36 is open; and the inlet 38 b and anoutlet 38 a of the fourth 3-way valve 38 are open. Accordingly, thesource gas S1 is supplied to the reaction chamber 10 together with thefirst carrier gas P1. Meanwhile, the purge gas P2 is continuouslysupplied to the reaction chamber 10 and the second carrier gas P3 isalso supplied to the reaction chamber 10 in a state where the fourthgate valve 48 is closed. Generally, in a 3-way valve, when one flow pathis closed, another flow path is open.

Thereafter, in a source gas purging stage, source gas residues that arenot attached to the surface of the substrate are removed from thereaction chamber 10. Here, the first gate valve 42 is open; the firstoutlet 32 a of the first 3-way valve 32 is closed (when a second outlet32 b of the first 3-way valve 32 is open according to the characteristicof a 3-way valve); the inlet 34 a of the second 3-way valve 34 is closed(when the outlet 34 b of the second 3-way valve 34 is open); the firstoutlet 36 a of the third 3-way valve 36 toward the bypass 16 is open(when a second outlet 36 b of the third 3-way valve 36 is open); and theinlet 38 b of the fourth 3-way valve 38 is closed (when the outlet 38 aof the fourth 3-way valve 38 is open). Accordingly, the residues of thesource gas S1 within the supply pipes flow to the bypass 16 togetherwith the first carrier gas P1 and the residues of the source gas S1within the reaction chamber 10 purged by the purge gas P2 continuouslysupplied to the reaction chamber 10. Here, the second carrier gas P3 isalso supplied to the reaction chamber 10 in a state where the fourthgate valve 48 is closed.

Subsequently, in a reactive gas pulsing stage, the reactive gas S2 issupplied into the reaction chamber 10 in a state where the source gas S1has been deposited on the surface of the substrate so that the sourcegas S1 reacts with part of the reactive gas S2, thereby forming areaction product on the surface of the substrate. Here, a supply linefor the first carrier gas P1 and the purge gas P2 is the same as that inthe source gas purging stage, with the exception that the fourth gatevalve 48 is open so that the reactive gas S2 is supplied into thereaction chamber 10 together with the second carrier gas P3. Meanwhile,the purge gas P2 is continuously supplied into the reaction chamber 10.

Subsequently, in a reactive gas purging stage, the residues of thereactive gas S2 other than the reaction product of the source gas S1 andthe reactive gas S2 deposited on the surface of the substrate areremoved from the reaction chamber 10. Here, a supply line for the firstcarrier gas P1 and the purge gas P2 is the same as that in the sourcegas purging stage. The fourth gate valve 48 is closed and only thesecond carrier gas P3 is supplied to the reaction chamber 10.

As described above, when one cycle of the source gas pulsing stage, thesource gas purging stage, the reactive gas pulsing stage, and thereactive gas purging stage is performed, the reaction product of thesource gas 51 and the reactive gas S2 is deposited to be very thin onthe surface of the substrate. Several or several thousands of cycles maybe performed to form a desired thin layer on the surface of thesubstrate.

However, the conventional ALD apparatus has a problem in that deadvolume (DV), in which purging is not performed and a source gas materialis stagnant between valves, occurs. In FIG. 2, a hatched portion betweenthe third 3-way valve 36 and the fourth 3-way valve 38 corresponds to aDV portion. In detail, when source gas purging starts after source gaspulsing in which the source gas S1 is supplied to the reaction chamber10 through the third 3-way valve 36 and the fourth 3-way valve 38, asdescribed above, supply of the source gas S1 is interrupted and thefirst carrier gas P1 is discharged through the bypass 16. Here, thesource gas S1 remains in the portion of the first carrier gas supplypipe 26 a corresponding to the DV portion between the third 3-way valve36 and the fourth 3-way valve 38. The remaining source gas is stillstagnant in the first carrier gas supply pipe 26 a during the succeedingreactive gas pulsing and purging stages. Only after a single ALD cycleis completed, the remaining source gas in the DV portion flows into thereaction chamber 10 when the outlet 38 b of the fourth 3-way valve 38 isopen in the source gas pulsing stage in a subsequent cycle.

When a gas material such as a source gas is stagnant in a DV portion fora long time, degradation occurs and an additional dummy process ofremoving the remaining source gas is required. In particular, when adielectric layer or a complex layer, which includes multiple layers madeof different materials, is formed using the conventional ALD apparatus,different source gas materials may react with each other in the DVportion, thereby generating unnecessary particles. As a result, a thinfilm formed through the ALD may have defects or low uniformity.

The source gas material remaining in the DV portion may be slowlydiffused and discharged, but it is not completely removed even afterseveral minutes. Taking into account that an ALD cycle takes severalseconds, it is very difficult to perform ALD using different kinds ofsource gas without purging and removing the source gas remaining in theDV portion.

SUMMARY OF THE INVENTION

The present invention provides an apparatus for fabricating asemiconductor device, by which purge efficiency is increased bypreventing dead volume from occurring in a gas valve system.

The present invention also provides a method of controlling a valve inthe apparatus for fabricating a semiconductor device, by which purgeefficiency is increased by preventing dead volume from occurring in agas valve system.

The present invention also provides a method of fabricating asemiconductor device, by which purge efficiency is increased bypreventing dead volume from occurring in a gas valve system of theapparatus.

According to a first aspect of the present invention, there is providedan apparatus for fabricating a semiconductor device. The apparatusincludes a reaction chamber in which a substrate is processed tofabricate a semiconductor device; a first processing gas supply pipesupplying a first processing gas into the reaction chamber; a 4-wayvalve having a first inlet, a second inlet, a first outlet, and a secondoutlet and installed at the first processing gas supply pipe such thatthe first inlet and the first outlet are connected to the firstprocessing gas supply pipe; a second processing gas supply pipeconnected to the second inlet of the 4-way valve to supply a secondprocessing gas; a bypass connected to the second outlet of the 4-wayvalve; and a gate valve installed at the bypass.

According to a second aspect of the present invention, there is providedan apparatus for fabricating a semiconductor device. The apparatusincludes a reaction chamber in which a substrate is processed tofabricate a semiconductor device; a purge gas supply pipe connected tothe reaction chamber to supply a purge gas to the reaction chamber; a4-way valve having a first inlet, a second inlet, a first outlet, and asecond outlet and installed at the purge gas supply pipe such that thefirst inlet and the first outlet are connected to the purge gas supplypipe; a source gas supply pipe connected to the second inlet of the4-way valve to supply a source gas to the reaction chamber; a firstcarrier gas supply pipe connected to the source gas supply pipe; areactive gas supply pipe connected to the reaction chamber to supply areactive gas to the reaction chamber; a second carrier gas supply pipeconnected to the reactive gas supply pipe; a discharge pipe connected tothe reaction chamber to discharge gas from the reaction chamber; adischarge pump installed at the discharge pipe; a bypass connected tothe second outlet of the 4-way valve and to the discharge pipe in frontof the discharge pump; and a gate valve installed at the bypass.

According to a third aspect of the present invention, there is provideda method of controlling a valve of the apparatus according to the firstaspect of the present invention. The method includes closing the gatevalve installed at the bypass and opening the 4-way valve while thesecond processing gas is supplied to the reaction chamber, and openingthe gate valve and closing the 4-way valve while supply of the secondprocessing gas to the reaction chamber is interrupted.

According to a fourth aspect of the present invention, there is provideda method of controlling a valve of the apparatus according to the secondaspect of the present invention. The method includes closing the gatevalve installed at the bypass and opening the 4-way valve while thesource gas is supplied to the reaction chamber, and opening the gatevalve and closing the 4-way valve while supply of the source gas to thereaction chamber is interrupted.

According to a fifth aspect of the present invention, there is provideda method of fabricating a semiconductor device using the apparatusaccording to the second aspect of the present invention. The methodincludes loading the substrate into the reaction chamber, attaching asource gas material to the substrate by supplying the source gas to thereaction chamber, purging a source gas material that is not attached tothe substrate by supplying the purge gas to the reaction chamber,forming a first reaction product layer on the substrate by supplying thereactive gas to the reaction chamber to allow the reactive gas to reactwith the source gas material attached to the substrate, and purging thereactive gas that has not reacted with the source gas material bysupplying the purge gas to the reaction chamber.

According to a sixth aspect of the present invention, there is providedan apparatus for fabricating a semiconductor device. The apparatusincludes a reaction chamber in which a substrate is processed tofabricate a semiconductor device; a purge gas supply pipe connected tothe reaction chamber to supply a purge gas to the reaction chamber; afirst 4-way valve having a first inlet, a second inlet, a first outlet,and a second outlet and installed at the purge gas supply pipe such thatthe first inlet and the first outlet are connected to the purge gassupply pipe; a second 4-way valve having a first inlet, a second inlet,a first outlet, and a second outlet and installed at the purge gassupply pipe such that the first inlet and the first outlet are connectedto the purge gas supply pipe and that the second 4-way valve isconnected to the first 4-way valve in series; a first source gas supplypipe and a second source gas supply pipe respectively connected to thesecond inlets of the respective first and second 4-way valves to supplya source gas to the reaction chamber; first carrier gas supply pipesrespectively connected to the first and second source gas supply pipes;a reactive gas supply pipe connected to the reaction chamber to supply areactive gas to the reaction chamber; a second carrier gas supply pipeconnected to the reactive gas supply pipe; a discharge pipe connected tothe reaction chamber to discharge gas from the reaction chamber; adischarge pump installed at the discharge pipe; a bypass comprising twobranches respectively connected to the second outlets of the respectivefirst and second 4-way valves and an end connected to the discharge pipein front of the discharge pump; and gate valves installed at the twobranches, respectively, of the bypass.

According to a seventh aspect of the present invention, there isprovided a method of fabricating a semiconductor device using theapparatus according to the sixth aspect of the present invention. Themethod includes loading the substrate into the reaction chamber,attaching a source gas material to the substrate by selectivelysupplying one of the first and second source gases to the reactionchamber, purging a source gas material that is not attached to thesubstrate by supplying the purge gas to the reaction chamber, forming afirst reaction product layer on the substrate by supplying the reactivegas to the reaction chamber to allow the reactive gas to react with thesource gas material attached to the substrate, and purging the reactivegas that has not reacted with the source gas material by supplying thepurge gas to the reaction chamber.

According to the present invention, a 4-way valve is formed at ajunction of a purge gas supply pipe and a source gas supply pipe and abypass is connected to one outlet of the 4-way valve so that dead volumecaused by the stagnation of a source gas is prevented. Even when thedead volume occurs, a gas material stagnant in a dead volume portion isnot supplied to a reaction chamber but is discharged through the bypass.Accordingly, purge efficiency is increased and reliable semiconductordevices can be fabricated.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of theinvention will be apparent from the more particular description ofpreferred aspects of the invention, as illustrated in the accompanyingdrawings in which like reference characters refer to the same partsthroughout the different views. The drawings are not necessarily toscale, emphasis instead being placed upon illustrating the principles ofthe invention.

FIG. 1 is a schematic diagram illustrating a gas valve system of aconventional apparatus for fabricating a semiconductor device.

FIG. 2 is an enlarged view of a part of the gas valve system in whichdead volume (DV) occurs.

FIG. 3 is a cross sectional view of the part shown in FIG. 2, takenalong the line AA′, in which a 2-way valve is closed.

FIG. 4 is a cross sectional view of the part shown in FIG. 2, takenalong the line AA′, in which the 2-way valve is open.

FIG. 5 is a schematic diagram illustrating an apparatus for fabricatinga semiconductor device according to a first embodiment of the presentinvention.

FIG. 6 is an enlarged view of an essential part of the apparatusillustrated in FIG. 5.

FIG. 7 is a cross sectional view of the part shown in FIG. 6, takenalong the line CC′, in which a 2-way valve is closed.

FIG. 8 is a cross sectional view of the part shown in FIG. 6, takenalong the line DD′, in which a 4-way valve is closed.

FIG. 9 is a schematic diagram illustrating an apparatus for fabricatinga semiconductor device according to a second embodiment of the presentinvention.

FIG. 10 is an enlarged view of an essential part of the apparatusillustrated in FIG. 9.

FIG. 11 is a cross sectional view of the part shown in FIG. 9, takenalong the line EE′, in which a 4-way valve is closed.

FIG. 12 is a schematic diagram illustrating an apparatus for fabricatinga semiconductor device according to a third embodiment of the presentinvention.

FIG. 13 is a schematic diagram illustrating an apparatus for fabricatinga semiconductor device according to a fourth embodiment of the presentinvention.

FIG. 14 is a schematic diagram illustrating an apparatus for fabricatinga semiconductor device according to a fifth embodiment of the presentinvention.

FIG. 15 is a schematic diagram illustrating an apparatus for fabricatinga semiconductor device according to a sixth embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention can be applied to any equipment that fundamentallysupplies a gas material into a reaction chamber and performssemiconductor fabrication processes in the reaction chamber using thegas material. Accordingly, the present invention can be widely used indeposition equipment such as chemical vapor deposition (CVD) or atomiclayer deposition (ALD) equipment and etching equipment. The followingexemplary embodiments of the present invention are described inconnection with ALD, but the invention is applicable to other processes.

FIG. 5 is a schematic diagram illustrating an apparatus for fabricatinga semiconductor device according to a first embodiment of the presentinvention. FIG. 6 is an enlarged view of a part of the apparatusillustrated in FIG. 5. FIG. 7 is a cross sectional view of the partshown in FIG. 6, taken along the line CC′, in which a 2-way valve isclosed. FIG. 8 is a cross sectional view of the part shown in FIG. 6,taken along the line DD′, in which a 4-way valve is closed.

The apparatus for fabricating a semiconductor device, a valve controlmethod, and a method of fabricating a semiconductor device using theapparatus, according to the first embodiment of the present inventionwill be described in detail with reference to FIGS. 5 through 8.

Referring to FIG. 5, a source gas supply source 122, a reactive gassupply source 124, a purge gas supply source 128, a first carrier gassupply source 126, and a second carrier gas supply source 130 supply asource gas, a reactive gas, a purge gas, and first and second carriergases, respectively, to a reaction chamber 110 via a source gas supplypipe 122 a, a reactive gas supply pipe 124 a, a purge gas supply pipe128 a, a first carrier gas supply pipe 126 a, and a second carrier gassupply pipe 130 a, respectively. Here, the source gas and the reactivegas used to form materials using ALD, and particularly, oxide materialssuch as SiO₂, Al₂O₃, Ta₂O₅, and HfO₂ and nitride materials such as SiN,TiN, and TaN, may be appropriately selected. For example, to formalumina (Al₂O₃) using ALD, trimethylaluminum (TMA) may be used as thesource gas and H₂O may be used as the reactive gas. According to amaterial to be formed, hydrogen plasma may be used as the reactive gasor oxygen plasma instead of H₂O may be used as a source of oxygen. Argongases are used as the purge gas and the first and second carrier gasesin this embodiment, but various gases may be used.

In the drawings and the following descriptions, fundamentally, a pipesection through which the source gas is supplied from the source gassupply source 122 to the reaction chamber 110 is referred to as thesource gas supply pipe 122 a; a pipe section through which the reactivegas is supplied from the reactive gas supply source 124 to the reactionchamber 110 is referred to as the reactive gas supply pipe 124 a; a pipesection through which the purge gas is supplied from the purge gassupply source 128 to the reaction chamber 110 is referred to as thepurge gas supply pipe 128 a; a pipe section through which the firstcarrier gas is supplied from the first carrier gas supply source 126 tothe reaction chamber 110 is referred to as the first carrier gas supplypipe 126 a; and a pipe section through which the second carrier gas issupplied from the second carrier gas supply source 130 to the reactionchamber 110 is referred to as the second carrier gas supply pipe 130 a.However, since two or more gases may be supplied through a single pipe,the pipe may have two or more reference names in the followingdescription.

In addition, although the reaction chamber 110 is not specificallyillustrated, it is designed such that a substrate, i.e., a wafer, usedto fabricate semiconductor devices is loaded and landed therein. Thereaction chamber 110 may be a single wafer type or batch type reactionchamber and may be combined with a device for inducing plasma within thereaction chamber 110. A discharge pump 112 is installed in the back ofthe reaction chamber 110 to control an inner pressure of the reactionchamber 110. A throttle valve 114 is installed between the reactionchamber 110 and the discharge pump 112 to maintain the inner pressure ofthe reaction chamber 110 constant.

In a source gas supply line, the first carrier gas supply pipe 126 a isconnected to the first carrier gas supply source 126 to supply thecarrier gas. The source gas supply source 122 is connected to the firstcarrier gas supply pipe 126 a in parallel through first and second 3-wayvalves 132 and 134. An on/off valve, i.e., a first gate valve 142 isinstalled between the first and second 3-way valves 132 and 134. Asource gas supply pipe 122 c in the back of the second 3-way valve 134is connected with the purge gas supply pipe 128 a through first andsecond inlets 150 c and 150 d of a 4-way valve 150. In FIG. 5, the 4-wayvalve 150 is illustrated functionally and includes the first and secondinlets 150 c and 150 d through which a gas material flows in and firstand second outlets 150 a and 150 b through which a gas material flowsout. The second outlet 150 b of the 4-way valve 150 is connected to thereaction chamber 110 and the first outlet 150 a of the 4-way valve 150is connected to a bypass 116. Another end of the bypass 116 is connectedto a discharge pipe 113 between the throttle valve 114 and the dischargepump 112. A fifth gate valve 152 is installed at the bypass 116.According to the on/off state of the first gate valve 142, the firstcarrier gas or the source gas is supplied to the reaction chamber 110 orthe bypass 116 via the 4-way valve 150.

In a purge gas supply line, the purge gas is supplied from the purge gassupply source 128 to the reaction chamber 110 through the purge gassupply pipe 128 a. The 4-way valve 150 is installed at a junction of thepurge gas supply pipe 128 a and the first carrier gas supply pipe 126 a.A second gate valve 144 is installed between the purge gas supply source128 and the 4-way valve 150.

In a reactive gas supply line, the second carrier gas is supplied fromthe second carrier gas supply source 130 to the reaction chamber 110through the second carrier gas supply pipe 130 a, and the reactive gasis supplied from the reactive gas supply source 124 to the reactionchamber 110 through the reactive gas supply pipe 124 a and the secondcarrier gas supply pipe 130 a to which the reactive gas supply pipe 124a is connected. A third gate valve 146 is installed between the reactionchamber 110 and the junction of the reactive gas supply pipe 124 a andthe second carrier gas supply pipe 130 a. A fourth gate valve 148 isinstalled between the junction and the reactive gas supply source 124.

The structure of the 4-way valve 150 and the fifth gate valve 152 andthe open/closed states of their inlets and outlets will be describedwith reference to FIGS. 5 through 8. FIG. 5 functionally illustrates theinlets and outlets of the 4-way valve 150 and the fifth gate valve 152according to a flow direction of supplied gas. FIGS. 6 through 8specifically illustrate the 4-way valve 150 and the fifth gate valve152.

The 4-way valve 150 and the fifth gate valve 152 are diaphragm valves inthe embodiment of the present invention, but the present invention isnot restricted thereto. A flow of a gas material according to on/offstates of the 4-way valve 150 and the fifth gate valve 152 will bedescribed.

As illustrated in FIG. 7, the fifth gate valve 152 installed at thebypass 116 does not allow the bypass 116 to directly penetrate the fifthgate valve 152 in a straight line but includes first and second verticalvia holes 152 h 1 and 152 h 2 to be vertically connected to the bypass116 side by side. The first and second vertical via holes 152 h 1 and152 h 2 extend to a top surface of a body 152 a. A diaphragm 152 c movedup and down by pressure is installed above the top surface of the body152 a through which the first and second vertical via holes 152 h 1 and152 h 2 are exposed within a housing 152 b to define a predeterminedspace.

When the fifth gate valve 152 is turned off, that is, when the diaphragm152 c moves downward and closely contacts the surface of the body 152 ato close the first and second vertical via holes 152 h 1 and 152 h 2, asshown in FIG. 7, a flow of a gas material through the bypass 116 isblocked. When the fifth gate valve 152 is turned on, that is, when thediaphragm 152 c moves upward and is separated from the surface of thebody 152 a to open the first and second vertical via holes 152 h 1 and152 h 2, a gas material can flow through the bypass 116. That is, a gasmaterial flowing into the bypass 116 via the first outlet 150 a of the4-way valve 150 flows out through the second vertical via hole 152 h 2,passes through a space between the top surface of the body 152 a and thediaphragm 152 c, and flows into the bypass 116 again via the firstvertical via hole 152 h 1.

As shown in FIGS. 5, 6, and 8, the 4-way valve 150 includes a firsthorizontal via hole 128 b connecting the second inlet 150 d and thesecond outlet 150 b, a first vertical via hole 150 h 1 extending fromthe middle of the first horizontal via hole 128 b to a top surface of abody 150 e, a third vertical via hole 150 h 3 communicating with thefirst inlet 150 c connected with the source gas supply pipe 122 c, asecond vertical via hole 150 h 2 communicating with the first outlet 150a connected with the bypass 116, and a second horizontal via hole 151connecting the upper portion of the second vertical via hole 150 h 2 andthe upper portion of the third vertical via hole 150 h 3. A housing 150f is formed above the body 150 e of the 4-way valve 150 to define apredetermined space. A diaphragm 150 g which can be moved up and down isinstalled within the space defined by the housing 150 f.

As illustrated in FIG. 8, when the 4-way valve 150 is turned off, thatis, when the diaphragm 150 g moves down and closely contacts the topsurface of the body 150 e to close the upper ends of the first throughthird vertical via holes 150 h 1 through 150 h 3, the purge gas issupplied to the reaction chamber 110 via the first horizontal via hole128 b, and the source gas or the first carrier gas flowing in the sourcegas supply pipe 122 c flows into the bypass 116 via the third verticalvia hole 150 h 3, the second horizontal via hole 151, and the secondvertical via hole 150 h 2. When the 4-way valve 150 is turned on, thatis, when the diaphragm 150 g moves up and is separated from the topsurface of the body 150 e to open the upper ends of the first throughthird vertical via holes 150 h 1 through 150 h 3, the purge gas flowsinto the reaction chamber 110 via the first horizontal via hole 128 b,and the source gas or the first carrier gas flows into the bypass 116through the third vertical via hole 150 h 3, the second horizontal viahole 151 or a space between the top surface of the body 150 a and thediaphragm 150 g, and the second vertical via hole 150 h 2 and into thereaction chamber 110 via the through the third vertical via hole 150 h3, the space between the top surface of the body 150 a and the diaphragm150 g, and the first vertical via hole 150 h 1. Here, when fifth gatevalve 152 is turned off, the first carrier gas or the source gas flowsonly to the reaction chamber 110 through the third vertical via hole 150h 3, the space between the top surface of the body 150 a and thediaphragm 150 g, and the first vertical via hole 150 h 1.

Selection between the source gas and the first carrier gas and selectionbetween the reactive gas and the second carrier gas will be describedbelow in connection with description of an ALD process.

The following describes in detail a process of depositing a reactionproduct of the source gas and the reactive gas on a surface of asubstrate using ALD. In performing the ALD process, a sequential set ofa source gas pulsing stage, a source gas purging stage, a reactive gaspulsing stage, and a reactive gas purging stage is defined as one cycle,and the cycles are repeated until a thin layer having a desiredthickness is formed.

In the source gas pulsing stage, the source gas is supplied to thereaction chamber 110 loaded with a wafer, i.e., the substrate (notshown), so that a source gas material is attached to the surface of thesubstrate. Here, the first gate valve 142 is turned off to be closed, afirst outlet 132 a of the first 3-way valve 132 is open, and a firstinlet 134 a and an outlet 134 b of the second 3-way valve 134 are open,so that the first carrier gas and the source gas are simultaneouslysupplied. In addition, the fifth gate valve 152 installed at the bypass116 is turned off while the 4-way valve 150 is turned on, so that a gasflow to the bypass 116 is blocked and a gas flow is introduced to thereaction chamber 110. As a result, the source gas is supplied to thereaction chamber 110 together with the first carrier gas. In oneembodiment, at the same time, the purge gas is continuously supplied tothe reaction chamber 110. The second carrier gas may be supplied to thereaction chamber 110 by closing the fourth gate valve 148 and openingthe third gate valve 146.

Subsequently, in the source gas purging stage, source gas residues thatare not attached to the surface of the substrate are removed from thereaction chamber 110. In this purging stage, the first gate valve 142 isopen; the first outlet 132 a of the first 3-way valve 132 is closedwhile a second outlet 132 b of the first 3-way valve 132 is open; andthe first inlet 134 a of the second 3-way valve 134 is closed while theoutlet 134 b of the second 3-way valve 134 is open, so that the supplyof the reactive gas is interrupted and the first carrier gas is allowedto flow. In addition, the fifth gate valve 152 installed at the bypass116 is turned on while the 4-way valve 150 is turned off, so that thefirst carrier gas is discharged through the bypass 116. Accordingly, thesource gas remaining between the second 3-way valve 134 and the 4-wayvalve 150 and between the 4-way valve 150 and the fifth gate valve 152does not flow into the reaction chamber 110 but is discharged throughthe bypass 116 together with the first carrier. The source gas remainingin the reaction chamber 110 without being deposited is purged by thepurge gas continuously supplied to the reaction chamber 110. Here, thesecond carrier gas may be continuously supplied to the reaction chamber110 in a state where the fourth gate valve 148 is closed.

Subsequently, in the reactive gas pulsing stage, the reactive gas issupplied into the reaction chamber 110 in a state where the source gashas been deposited on the surface of the substrate so that the sourcegas reacts with part of the reactive gas, thereby forming a reactionproduct on the surface of the substrate. Here, similarly to the sourcegas purging stage, the first carrier gas is discharged through thebypass 116 and the purge gas is continuously supplied to the reactionchamber 110. However, in the reactive gas pulsing stage, the fourth gatevalve 148 installed at the reactive gas supply line and the third gatevalve 146 are open so that the reactive gas is supplied to the reactionchamber 110 together with the second carrier gas.

Subsequently, in the reactive gas purging stage, the residues of thereactive gas other than the reaction product of the source gas and thereactive gas deposited on the surface of the substrate are removed fromthe reaction chamber 110. Here, similarly to the source gas purgingstage, the first carrier gas is discharged through the bypass 116 andthe purge gas is continuously supplied to the reaction chamber 110.However, in the reactive gas purging stage, the fourth gate valve 148 atthe reactive gas supply line is closed to interrupt the supply of thereactive gas. As a result, only the second carrier gas is supplied tothe reaction chamber 110.

As described above, when a cycle of the source gas pulsing stage, thesource gas purging stage, the reactive gas pulsing stage, and thereactive gas purging stage is performed, the reaction product of thesource gas and the reactive gas is deposited to be very thin on thesurface of the substrate. Several or several thousands of cycles may beperformed to form a desired thin layer on the surface of the substrate.In the above-described embodiment of the present invention, a singlelayer is formed on the substrate through the ALD process using a singlesource gas. For example, when the source gas, the reactive gas, and thereaction product of the source gas and the reactive gas are representedby “A”, “B”, and “AB”, respectively, a layer deposited on the substrateaccording to the first embodiment of the present invention may berepresented by “AB/AB/AB/AB . . . AB/AB”.

FIG. 9 is a schematic diagram illustrating an apparatus for fabricatinga semiconductor device according to a second embodiment of the presentinvention. FIG. 10 is an enlarged view of a part of the apparatusillustrated in FIG. 9. FIG. 11 is a cross sectional view of the partshown in FIG. 9, taken along the line EE', in which a 4-way valve isclosed. The second embodiment is the same as the first embodiment, withthe exception that the structure of the 4-way valve 154 and thedisposition of the purge gas supply line and the source gas supply lineare different from those in the first embodiment. The differences willbe described below.

Referring to FIGS. 9 through 11, the source gas supply line, the purgegas supply line, and the reactive gas supply line in the secondembodiment are substantially similar to those in the first embodiment,but the structure and connection relationship of the 4-way valve 154 isdifferent. In detail, in the first embodiment, the 4-way valve 150includes the first horizontal via hole 128 b formed straight to beconnected to the purge gas supply pipe 128 a. In contrast, in the secondembodiment, the 4-way valve 154 includes a second horizontal via hole154 f that communicates with a second inlet 154 d of the 4-way valve 154and bends at a right angle within the 4-way valve 154. A second verticalvia hole 154 h 2 is formed extending from the middle of the secondhorizontal via hole 154 f to a top surface of a body 154 g of the 4-wayvalve 154. A first horizontal via hole 154 e communicating with a firstinlet 154 c connected with the source gas supply pipe 122 c is formed tobend at a right angle within the 4-way valve 154. A first vertical viahole 154 h 1 is formed extending from the middle of the first horizontalvia hole 154 e to the top surface of the body 154 g.

As illustrated in FIG. 11, when the 4-way valve 154 is turned off, thatis, when a diaphragm 154 i moves down and closely contacts the topsurface of the body 154 g to close the upper ends of the first andsecond vertical via holes 154 h 1 and 154 h 2, the purge gas is suppliedto the reaction chamber 110 via the second horizontal via hole 154 f,and the source gas or the first carrier gas flowing in the source gassupply pipe 122 c flows into the bypass 116 via the first horizontal viahole 154 e. When the 4-way valve 154 is turned on, that is, when thediaphragm 154 i moves up and is separated from the top surface of thebody 154 g to open the upper ends of the first and second vertical viaholes 154 h 1 and 154 h 2, the purge gas flows into the reaction chamber110 via the second horizontal via hole 154 f or into the bypass 116through the second horizontal via hole 154 f, the second vertical viahole 154 h 2, a space between the top surface of the body 154 g and thediaphragm 154 i, and the first vertical via hole 154 h 1. When the fifthgate valve 152 is turned off, the purge gas flows only into the reactionchamber 110. Meanwhile, the source gas or the first carrier gas flowingin the source gas supply pipe 122 c flows into the reaction chamber 110through the first vertical via hole 154 h 1, the space between thesurface of the body 154 g and the diaphragm 154 i, and the secondvertical via hole 154 h 2 or into the bypass 116 through the firsthorizontal via hole 154 e. Here, when the fifth gate valve 152 is turnedoff, the first carrier gas or the source gas flows only to the reactionchamber 110 through the first vertical via hole 154 h 1, the spacebetween the surface of the body 154 g and the diaphragm 154 i, and thesecond vertical via hole 154 h 2.

The following describes in detail the closed and open states of eachvalve in each stage of a process of depositing a reaction product of thesource gas and the reactive gas on a surface of a substrate using ALD.

In the source gas pulsing stage, the first gate valve 142 is turned offto be closed, a first outlet 132 a of the first 3-way valve 132 is open,and a first inlet 134 a and an outlet 134 b of the second 3-way valve134 are open, so that the first carrier gas and the source gas aresimultaneously supplied. In addition, the fifth gate valve 152 installedat the bypass 116 is turned off and closed while the 4-way valve 154 isturned on, so that a gas flow to the bypass 116 is blocked and a gasflow is introduced to the reaction chamber 110. As a result, the sourcegas is supplied to the reaction chamber 110 together with the firstcarrier gas. Meanwhile, the purge gas is continuously supplied to thereaction chamber 110. The second carrier gas may be supplied to thereaction chamber 110 by closing the fourth gate valve 148 and openingthe third gate valve 146.

Subsequently, in the source gas purging stage, the first gate valve 142is open; the first outlet 132 a of the first 3-way valve 132 is closedwhile a second outlet 132 b of the first 3-way valve 132 is open; andthe first inlet 134 a of the second 3-way valve 134 is closed while theoutlet 134 b of the second 3-way valve 134 is open, so that the supplyof the reactive gas is interrupted and the first carrier gas is allowedto flow. In addition, the fifth gate valve 152 installed at the bypass116 is turned on while the 4-way valve 154 is turned off, so that thefirst carrier gas is discharged through the bypass 116. Accordingly, thesource gas remaining between the second 3-way valve 134 and the 4-wayvalve 154 and between the 4-way valve 154 and the fifth gate valve 152does not flow into the reaction chamber 110 but is discharged throughthe bypass 116 together with the first carrier gas. The source gasremaining in the reaction chamber 110 without being deposited is purgedby the purge gas continuously supplied to the reaction chamber 110.Here, the second carrier gas may be continuously supplied to thereaction chamber 110 in a state where the fourth gate valve 148 isclosed.

In the reactive gas pulsing and purging stages, similarly to the sourcegas purging stage, the first carrier gas is discharged through thebypass 116 and the purge gas is continuously supplied to the reactionchamber 110. However, in the reactive gas pulsing and purging stages,the fourth gate valve 148 installed at the reactive gas supply line andthe third gate valve 146 are open so that the reactive gas is suppliedto the reaction chamber 110 together with the second carrier gas.

FIG. 12 is a schematic diagram illustrating an apparatus for fabricatinga semiconductor device according to a third embodiment of the presentinvention. The third embodiment is substantially similar to the firstembodiment illustrated in FIGS. 5 through 8 but relates to a process offorming a multilayer or a complex layer on a substrate through ALD usingdifferent kinds of source gas. The difference between the first andthird embodiments will be described below.

Referring to FIG. 12, each of two source gas supply sources 122 and 222is installed together with the first carrier gas supply line to beparallel with the source gas supply pipe 122 c and the two source gassupply sources 122 and 222 are disposed symmetrically. The apparatusillustrated in FIG. 12 is designed such that one of a first source gasand a second source gas is selectively supplied using a plurality of2-way gate valves and 3-way valves. In the third embodiment, two kindsof source gas are supplied, but more than two kinds of source gas may beselectively supplied by disposing more than two source supply lines inparallel with the source gas supply pipe 122 c.

In a first source gas supply line starting from the first source gassupply source 122 supplying the first source gas, the carrier gas issupplied from the first carrier gas supply source 126 through the firstcarrier gas supply pipe 126 a to which the first source gas supplysource 122 is connected in parallel through first through fourth 3-wayvalves 132, 134, 136, and 138. An on/off valve, i.e., the first 2-waygate valve 142, is installed at the first carrier gas supply pipe 126 abetween the first and second 3-way valves 132 and 134. An on/off valve,i.e., a second 2-way gate valve 242, is installed between the third andfourth 3-way valves 136 and 138. The first source gas supply source 122is installed between the third and fourth 3-way valves 136 and 138 to bein parallel with the second 2-way gate valve 242.

In a second source gas supply line starting from the second source gassupply source 222 supplying the second source gas, the carrier gas issupplied from the first carrier gas supply source 126 through the firstcarrier gas supply pipe 126 a to which the second source gas supplysource 222 is connected in parallel through fifth through eighth 3-wayvalves 232, 234, 236, and 238. In detail, the fifth 3-way valve 232 isdisposed between the first carrier gas supply source 126 and the first3-way valve 132. The sixth 3-way valve 234 is disposed between thesecond 3-way valve 134 and the 4-way valve 150. The seventh 3-way valve236 and the eighth 3-way valve 238 are installed at the second sourcegas supply line that is in parallel with the first carrier gas supplypipe 126 a. An on/off valve, i.e., a third 2-way gate valve 442, isinstalled between the seventh and eighth 3-way valves 236 and 238. Thesecond source gas supply source 222 is installed between the seventh andeighth 3-way valves 236 and 238 to be in parallel with the third 2-waygate valve 442.

In the third embodiment illustrated in FIG. 12, a single cycle of thesource gas pulsing stage, the source gas purging stage, the reactive gaspulsing stage, and the reactive gas purging stage is performed using thefirst source gas, thereby depositing a thin reaction product of thefirst source gas and the reactive gas on a surface of a substrate.Thereafter, the cycle is repeated using the second source gas, therebydepositing a reaction product of the second source gas and the reactivegas on the reaction product of the first source gas and the reactivegas. Several through several thousands of cycles are performed while thefirst and second source gases are alternately supplied to form a complexlayer on the surface of the substrate. For example, when the firstsource gas, the second source gas, the reactive gas, the reactionproduct of the first source gas and the reactive gas, and the reactionproduct of the second source gas and the reactive gas are represented by“A1”, “A2”, “B”, “A1B”, and “A2B”, respectively, a layer deposited onthe substrate according to the third embodiment of the present inventionmay be represented by “A1B/A2B/A1B/A2B . . . A1B/A2B”.

The following describes in detail a process of depositing a reactionproduct of the source gas and the reactive gas on a surface of asubstrate through ALD using the first and second source gases A1 and A2and the reactive gas B. In performing the ALD process, a sequential setof a source gas pulsing stage, a source gas purging stage, a reactivegas pulsing stage, and a reactive gas purging stage is defined as onecycle and the cycles are repeated until a thin layer having a desiredthickness is formed.

In a first source gas pulsing stage, the first source gas A1 is suppliedto the reaction chamber 110 loaded with a wafer, i.e., the substrate(not shown), so that a first source gas material is attached to thesurface of the substrate. Here, a second outlet 232 b of the fifth 3-wayvalve 232 and an outlet 234 b of the sixth 3-way valve 234 are open; thefirst 2-way gate valve 142 is turned off and closed; the first outlet132 a of the first 3-way valve 132 is open; the first inlet 134 a andthe outlet 134 b of the second 3-way valve 134 are open while a firstoutlet 136 a of the third 3-way valve 136 and an inlet 138 a of thefourth 3-way valve 138 are open; and the second 2-way gate valve 242 isturned off, so that the first carrier gas and the first source gas A1are supplied at the same time. In addition, the fifth gate valve 152installed at the bypass 116 is turned off while the 4-way valve 150 isturned on, so that a gas flow to the bypass 116 is blocked and a gasflow is introduced to the reaction chamber 110. As a result, the firstsource gas A1 from the first source gas supply source 122 is supplied tothe reaction chamber 110 together with the first carrier gas.

Subsequently, in the first source gas purging stage, source gas residuesthat are not attached to the surface of the substrate are removed fromthe reaction chamber 110. Here, the second outlet 232 b of the fifth3-way valve 232 and the outlet 234 b of the sixth 3-way valve 234 areopen; the first 2-way gate valve 142 is turned on and is open; the firstoutlet 132 a of the first 3-way valve 132 is closed while the secondoutlet 132 b of the first 3-way valve 132 is open; and the first inlet134 a of the second 3-way valve 134 is closed while the outlet 134 b isopen, so that the supply of the first source gas A1 is interrupted andthe first carrier gas is allowed to flow. In addition, the fifth gatevalve 152 installed at the bypass 116 is turned on while the 4-way valve150 is turned off, so that the first carrier gas is discharged throughthe bypass 116. As a result, the first source gas A1 remaining betweenthe second 3-way valve 134 and the 4-way valve 150 and between the 4-wayvalve 150 and the fifth gate valve 152 at the bypass 116 does not flowinto the reaction chamber 110 but is discharged through the bypass 116together with the first carrier gas. The first source gas A1 remainingin the reaction chamber 110 without being deposited is purged by thepurge gas continuously supplied from the purge gas supply source 128 tothe reaction chamber 110.

Subsequently, in the reactive gas pulsing stage, the reactive gas B issupplied into the reaction chamber 110 in a state where the first sourcegas A1 has been deposited on the surface of the substrate so that thefirst source gas A1 reacts with part of the reactive gas B, therebyforming the reaction product A1B on the surface of the substrate. Here,similarly to the first source gas purging stage, the first carrier gasis discharged through the bypass 116 and the purge gas is continuouslysupplied to the reaction chamber 110. However, in the reactive gaspulsing stage, the fourth gate valve 148 installed at the reactive gassupply line and the third gate valve 146 are open so that the reactivegas B is supplied to the reaction chamber 110 together with the secondcarrier gas supplied from the second carrier gas supply source 130.

Subsequently, in the reactive gas purging stage, the residues of thereactive gas B other than the reaction product A1B of the first sourcegas A1 and the reactive gas B deposited on the surface of the substrateare removed from the reaction chamber 110. Here, similarly to the firstsource gas purging stage, the first carrier gas is discharged throughthe bypass 116 and the purge gas is continuously supplied to thereaction chamber 110. However, in the reactive gas purging stage, thefourth gate valve 148 at the reactive gas supply line is closed tointerrupt the supply of the reactive gas. As a result, only the secondcarrier gas is supplied to the reaction chamber 110.

In a second source gas pulsing stage, the second source gas A2 issupplied to the reaction chamber 110 so that a second source gasmaterial is attached to the surface of the substrate on which thereaction product A1B has been formed. Here, the first outlet 132 a ofthe first 3-way valve 132 and the first gate valve 142 are closed; afirst outlet 232 a of the fifth 3-way valve 232 is open; and a firstoutlet 236 a of the seventh 3-way valve 236 is open. In this state, thefirst carrier gas and the second source gas A2 are simultaneouslysupplied to the reaction chamber 110 through the eighth 3-way valve 238and the sixth 3-way valve 234 and through analogous open/closed statesof valves as those in the first source gas pulsing stage.

A second source gas purging stage, the reactive gas pulsing stage, andthe reactive gas purging stage are performed in the same manner asdescribed above with respect to the first source gas, thereby formingthe reaction product A2B on the reaction product A1B. In this way, whenthe cycle is repeated while the first and second sources gases A1 and A2are alternately supplied, ALD is performed in the order of A1B, A2B,A1B, A2B . . . .

FIG. 13 is a schematic diagram illustrating an apparatus for fabricatinga semiconductor device according to a fourth embodiment of the presentinvention. In the third embodiment illustrated in FIG. 12, differentkinds of source gases are supplied to the reaction chamber 110 throughthe one source gas supply pipe 122 c and the one 4-way valve 150.However, in the fourth embodiment illustrated in FIG. 13, although theone purge gas supply pipe 128 a is used to supply different kinds ofsource gases, the different kinds of source gases are separatelysupplied to the reaction chamber 110 through first and second source gaspipes 122 c and 222 c and first and second 4-way valves 150 and 250.

In a first source gas supply line, the carrier gas is supplied from thefirst carrier gas supply source 126 through the first carrier gas supplypipe 126 a to which the first source gas supply source 122 is connectedin parallel through first through fourth 3-way valves 132, 134, 136, and138. An on/off valve, i.e., the first 2-way gate valve 142, is installedat the first carrier gas supply pipe 126 a between the first and second3-way valves 132 and 134. An on/off valve, i.e., a second 2-way gatevalve 143, is installed between the third and fourth 3-way valves 136and 138. The first source gas supply source 122 is installed between thethird and fourth 3-way valves 136 and 138 to be in parallel with thesecond 2-way gate valve 143. A first source gas from the first sourcegas supply source 122 is connected to the first 4-way valve 150.

In a second source gas supply line, a carrier gas is supplied from asecond carrier gas supply source 226 through a second carrier gas supplypipe 226 a to which the second source gas supply source 222 is connectedin parallel through the fifth through eighth 3-way valves 232, 234, 236,and 238. An on/off valve, i.e., the third 2-way gate valve 242, isinstalled at the second carrier gas supply pipe 226 a between the fifthand sixth 3-way valves 232 and 234. An on/off valve, i.e., a fourth2-way gate valve 243, is installed between the seventh and eighth 3-wayvalves 236 and 238. The second source gas supply source 222 is installedbetween the seventh and eighth 3-way valves 236 and 238 in parallel withthe fourth 2-way gate valve 243. A second source gas from the secondsource gas supply source 222 is connected to the second 4-way valve 250.The first and second 4-way valves operate according to the sameprinciple as that used in the first embodiment.

In a purge gas supply line, the purge gas is supplied from the purge gassupply source 128 to the reaction chamber 110 through the purge gassupply pipe 128 a. The first 4-way valve 150 is installed at a junctionof the purge gas supply pipe 128 a and the first source gas supply pipe122 c. The second 4-way valve 250 is installed at a junction of thepurge gas supply pipe 128 a and the second source gas supply pipe 222 c.The second gate valve 144 is installed between the purge gas supplysource 128 and the second 4-way valve 250. In addition, gate valves 152and 252 are installed at the bypass 116 connected with the first andsecond 4-way valves 150 and 250. A reactive gas supply line in thefourth embodiment is the same as those in the above-describedembodiments.

The following describes in detail a process of depositing a reactionproduct of the source gas and the reactive gas on a surface of asubstrate through ALD using the first and second source gases A1 and A2and the reactive gas B, according to the fourth embodiment of thepresent invention.

In a first source gas pulsing stage, the first source gas A1 is suppliedthrough the source gas supply pipe 122 c in the same manner as that usedin the third embodiment in a state where an inlet 250 c of the second4-way valve 250 is turned off.

Thereafter, a first source gas purging stage, a reactive gas pulsingstage, and a reactive gas purging stage are performed in the same manneras that used in the third embodiment, thereby forming a reaction productA1B on the surface of the substrate.

The first source gas line is blocked and a second source gas line isopen to perform a second source gas pulsing stage. Here, the inlet 150 cof the first 4-way valve 150 is closed and the inlet 250 c of the second4-way valve 250 is open.

Subsequently, a second source gas purging stage, the reactive gaspulsing stage, and the reactive gas purging stage are performed in thesame manner as that performed with respect to the first source gas A1,thereby performing ALD in order of A1B, A2B, A1B, A2B, . . . .

FIG. 14 is a schematic diagram illustrating an apparatus for fabricatinga semiconductor device according to a fifth embodiment of the presentinvention. An operating principle of the 4-way valve 154 in the fifthembodiment is the same as that in the second embodiment. In addition,the fifth embodiment is the same as the third embodiment in thatdifferent kinds of source gases are selectively supplied through thesingle source gas supply pipe 122 c. Thus, a detailed description of thefifth embodiment will not be repeated.

FIG. 15 is a schematic diagram illustrating an apparatus for fabricatinga semiconductor device according to a sixth embodiment of the presentinvention. An operating principle of the first and second 4-way valve154 and 254 in the sixth embodiment is the same as that in the secondembodiment. In addition, the sixth embodiment is the same as the fourthembodiment in that different kinds of source gases are selectivelysupplied through different source gas supply lines, respectively. Thus,a detailed description of the sixth embodiment will not be repeated.

In the third through sixth embodiments of the present invention, asdescribed above, a complex layer is formed on a substrate through ALDusing two kinds of source gases. However, more than two kinds of sourcegases may be selectively supplied when necessary. In addition, at leasttwo kinds of reactive gases may be selectively used. Here, to increasepurge efficiency, a reactive gas supply line may use the same gas valvesystem as a source gas supply line.

Moreover, in the third through sixth embodiments of the presentinvention, according to the foregoing description, an ALD cycle using afirst source gas alternates with an ALD cycle using a second source gas.However, a plurality of ALD cycles using the first source gas may beperformed to form a first thin layer to a predetermined thickness, andthen a plurality of ALD cycles using the second source gas may beperformed to form a second thin layer to a predetermined thickness onthe first thin layer.

For example, when a first source gas, a second source gas, a firstreactive gas, a second reactive gas, a reaction product of the firstsource gas and the first reactive gas, and a reaction product of thesecond source gas and the second reactive gas are represented by “A1”,“A2”, “B1”, “B2”, “A1B1”, and “A2B2”, respectively, a layer deposited ona substrate according to embodiments of the present invention may havediverse structures represented by “A1B1/A2B2/A1B1/A2B2 . . . A1B1/A2B2”,“A1B1/A1B2/A1B1/A1B2 . . . A1B1/A1B2”, “A1B1/A1B1 . . . /A1B1/A2B2/A2B2. . . A2B2”, etc. according to a combination of a source gas and areactive gas.

Different kinds of source gases are supplied using the two 4-way valves150 and 250 in the fourth embodiment of the present invention and thetwo 4-way valves 154 and 254 in the sixth embodiment of the presentinvention. Here, a stickier source gas among the first and second sourcegases may be supplied through a source gas supply line nearer to thereaction chamber 110. Generally, ZrO₂ is stickier than HfO₂ and HfO₂ isstickier than Al₂O₃.

To prove that dead volume is eliminated from a valve system according tothe present invention, HfO layers and AlO layers were formed using ALDaccording to the first embodiment. Table 1 shows the characteristics ofthe layers.

TABLE 1 Switching information Number Thickness Uniformity DepositionMaximum/ (27 MHz) of cycles (Å) (%) rate (Å/cycle) Minimum HfO {circlearound (1)}0.3/0.5/0.2/1.0/0.2 100 91.33 1.48 0.91 92.88/90.19 {circlearound (2)}(0.3/0.5/0.2/1.0/0.2) + 100 88.66 1.29 0.89 89.97/87.681.0/0.5/0.2/1.0/0.2 AlO {circle around (3)}0.1/0.3/1.0 100 141.25 1.681.41 143.09/138.34 {circle around (4)}(0.1/0.3/1.0) + 100 142.38 1.521.42 143.95/139.63 1.0/0.3/1.0

In Table 1, (1) and (2) denote cases where a HfO layer is formed usingALD: case (1) is a result of performing 100 cycles of source gas pulsing(0.3 seconds)/source gas purging (0.5 seconds)/oxygen pre-pulsing (0.2seconds)/oxygen plasma (0.1 second)/oxygen purging (0.2 seconds); andcase (2) is a result of additionally performing a cycle that does notsupply a source gas between cycles that supply the source gas. Theresult (2) proves that dead volume does not occur and uniformity is notdegraded in the valve system according to the present invention.

Similarly, results (3) and (4) of forming an AlO layer using ALD alsoprove that dead volume does not occur in the valve system according tothe present invention.

As described above, according to the present invention, a source gasremaining in a supply pipe of a source gas supply line is not allowed toflow into a reaction chamber but is discharged through a bypass, therebypreventing dead volume. Therefore, an additional load of purging deadvolume occurring in conventional technology is eliminated. As a result,fabrication of semiconductor devices can be performed more reliably.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeof the present invention as defined by the following claims.

1. A method of forming a semiconductor using atomic layer deposition,the method comprising: supplying a source gas through a first path to achamber; supplying a first purge gas through a second path to adischarge pump; supplying a reactive gas through a third path to thechamber; and supplying a second purge gas through a fourth path to thechamber, wherein the second path and the fourth path intersect.
 2. Themethod of claim 1, wherein a portion of the first path and a portion ofthe second path converge to share a common path so that the first purgegas purges the source gas from the common path.
 3. The method of claim1, wherein first purge gas purges the source gas from the first path andthe second purge gas purges the source gas and the reactive from thechamber.
 4. The method of claim 1, wherein the first path, the secondpath and the fourth path intersect at a valve.
 5. The method of claim 4,wherein the valve is a 4-way diaphragm valve.
 6. The method of claim 5,wherein the first path is passes through a first inlet and a firstoutlet of the 4-way diaphragm valve, the second path passes through thefirst inlet and a second outlet of the 4-way diaphragm valve, and thefourth path passes through a second inlet and the first outlet of the4-way diaphragm valve.
 7. The method of claim 4, wherein the source gasis supplied through the first path to the chamber when the 4-waydiaphragm valve is set in a first state, and the first purge gas issupplied through the second path to the discharge pump when the 4-waydiaphragm valve is set in a second state.
 8. The method of claim 7,wherein the second purge gas is continuously supplied to the chamberwhen the valve is set to the first state and when the valve is set tothe second state.
 9. A method of forming a semiconductor using atomiclayer deposition, the method comprising: supplying a source gas througha first path to a reaction chamber; supplying a first purge gas througha second path to a bypass of the reaction chamber, wherein the secondpath includes a first portion of the first path and the first purge gaspurges the source gas from the first portion the first path; supplying asecond purge gas through a third path to the reaction chamber to purgethe source gas from the reaction chamber, wherein the third pathincludes a second portion of the first path and the second purge gaspurges the source gas from the reaction chamber and the second portionof the first path; and supplying a reactive gas through a fourth path tothe reaction chamber.
 10. The method of claim 9, wherein the first path,the second path and the third path intersect at and pass through a 4-wayvalve.
 11. The method of claim 10, wherein the first path passes througha first inlet and a first outlet of the 4-way valve, the second pathpasses through the first inlet and a second outlet of the 4-way valve,and the third path passes through a second inlet and the first outlet ofthe 4-way valve.
 12. The method of claim 11, wherein the 4-way valve isset in a first state when the source gas is supplied through the firstpath to the reaction chamber, and the 4-way valve is set in a secondstate when the first purge gas is supplied through the second path tothe bypass.
 13. The method of claim 12, wherein the second purge gas iscontinuously supplied through the third path to the reaction chamberwhen the 4-way valve is set to the first state and when the 4-way valveis set to the second state.
 14. The method of claim 9, furthercomprising interrupting the supplying of the reactive gas, and supplyingthe second purge gas through the third path to the reaction chamber topurge the reactive gas from the reaction chamber.
 15. The method ofclaim 9, wherein the first purge gas is a carrier gas, and wherein themethod further comprises supplying the carrier gas through the firstpath to the reaction chamber during the supplying of the source gasthrough the first path to the reaction chamber.
 16. A method of forminga semiconductor using atomic layer deposition in an apparatus comprisinga reaction chamber, a 4-way valve, a first path connected to an a firstinlet of the 4-way valve, a second path connected to a second inlet ofthe 4-way valve, a third path connected between a first outlet of the4-way valve and the reaction chamber, and a fourth path connected to asecond outlet of the 4-way valve and bypassing the reaction chamber, themethod comprising: supplying a source gas to the reaction chamberthrough the first path and the third path when the 4-way valve is in afirst state; supplying a first purge gas through the first path tofourth path when the 4-way valve is in a second state to purge thesource gas from the first path; supplying a second purge to the reactionchamber through the second path and the third path to purge the sourcegas from the reaction chamber; and supplying a reactive gas through afifth path to the reaction chamber.
 17. The method of claim 16, furthercomprising interrupting the supplying of the reactive gas, and supplyingthe second purge gas through the second path and the third path to thereaction chamber to purge the reactive gas from the reaction chamber.18. The method of claim 16, further comprising supplying a carrier gasthrough the first path and the third path to the reaction chamber duringthe supplying of the source gas through the first path and the thirdpath to the reaction chamber.
 19. The method of claim 18, furthercomprising interrupting the supplying of the source gas through thefirst path and the third path to the reaction chamber, wherein the firstpurge gas is the carrier gas.
 20. A method of forming a semiconductorusing atomic layer deposition in an apparatus comprising a reactionchamber, a 4-way valve, and a bypass path bypassing the reactionchamber, the method comprising: supplying a source gas to the reactionchamber via a first path that passes through the 4-way valve; supplyinga first purge gas to the bypass path via a second path that passesthrough the 4-way valve and includes a first portion of the first path,wherein the first purge gas purges the source gas from the first portionof the first path; supplying a second purge gas to the reaction chambervia a third path that passes through the 4-way valve and includes asecond portion of the first path, wherein the second purge gas purgesthe source gas from the reaction chamber and the second portion of thefirst path; and supplying a reactive gas to the reaction chamber via afourth path.